Pomocy ! Jak to zrobić \frac{1}{1- \cos\alpha} +\frac{1}{1+\cos\alpha}=\frac{2}{\sin^2\alpha}
źródło:
\frac{1}{1- \cos\alpha} +\frac{1}{1+\cos\alpha}=\frac{2}{\sin^2\alpha}
L=\frac{1}{1- \cos\alpha} +\frac{1}{1+\cos\alpha}=\frac{1+\cos\alpha+1- \cos\alpha}{(1- \cos\alpha)(1+\cos\alpha)}=\frac{2}{1^2-\cos^2\alpha}=\frac{2}{sin^2\alpha}=P